The search for missing Malaysia Airlines flight MH370 is set to continue over the Easter long weekend, with officials denying reports efforts are winding down.

The unmanned submarine Bluefin-21, currently tasked with mapping the ocean floor for wreckage, completed its first full mission overnight.

It will be a relief to search authorities after the first two missions were aborted due to technical problems.

Image Caption:The planned search area off the coast of western Australia

Malaysian transport minister Hishammuddin Hussein said in a news conference on Thursday that the underwater search would be intensified in the coming days and passengers' relatives would be kept up to date on the developments.

The submersible spent 16 hours on the ocean floor and has mapped a total area of 90 sq km, according to a spokesman for the Joint Air Coordination Centre (JACC) in Perth, western Australia.

Video:MH370 Search: "We Will Not Stop"

"Both the aerial and underwater search activities for missing flight MH370 will continue over the Easter long weekend," he said.

"Any decision on ceasing search activities will be made in conjunction with our international partners.

"At the moment, we are focused on pursuing the best lead we have in relation to missing flight MH370.

"The Autonomous Underwater Vehicle is searching the ocean floor in the vicinity where the four signal detections were made by the towed pinger locator deployed by Australian defence vessel Ocean Shied.

"It is important this lead is pursued vigorously so we can either confirm or discount the area as the final resting place of MH370."

Oil samples taken from a slick in the Indian Ocean have now reached the Perth mainland and will be compared to engine oil used in the Malaysian Boeing 777 fleet.

If the samples match it would be the first sign of the missing jet since it went missing on March 8 en route to Beijing with 239 people on board.